Riquid-level-indicating system



Jan. 22, 1929.

J. D. SARTAKOFF LIQUID LEVEL INDICATING SYSTEM Filed June 29, 1926 3 Sheets-Sheet 1 INVENTO Jack jar/sta 1926 3 Sheets-Sheet 2 [NVEN 0R. Jack a Jig/Mia Jan. 22, 1929.

J. D. SARTAKOFF LIQUID LEVEL INDICATING SYSTEM Filed June 29 Jan. 22, 1929.

J. D. SARTAKOFF LIQUIQ LEVEL INDICATING SYSTEM Filed June 29, 1926 3 Sheets-Sheet INVENTOR. Jack 0. .Sarzak r7 AT RNEYS.

Patented Jan. 22, 1929.

UNITED STATES PATENT OFFICE.

J'AQK D. SARTAKOFF, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, OF

ONE-HALF TO KHETAH CORPORATION,

NEW YORK.

OF NEW YORK, N. Y., A CORPORATION OF LIQUID-LEVEL-INDICATIN G SYSTEM.

Application filed June This invention relates to indicating systoms, and more particularly those for indieating the level or quantity of liquid in tanks and other vessels at points remote from the vessels containing such liquids. V p Y The invention is adapted to be used in connect-ion with the measurement of any liquid, but is particularly intended for use in the measuring of gasoline contained within the underground supply tanks in garages, filling stations, etc. Theinvention is not, however, limited to use with underground storage tanks, but is adapted for broad general application. Y Z f The object of the invention isf'to' provide simple and reliable measuringorindicating apparatus adapted to be positioned at a 'distance froin'the. liquids; to be meas 'red and susceptible of installation in' anl oifi eej of the garage, factory or filling Statiomsothat the person in charge may readilya'scertainthe amount of liquid in the tank or tanks' foiiming part of the system without recourse to'ineasuring sticks and othersimilar adjuncts".

An important featureof'the presentinvention resides in the fact that the system may be associated with tanks from which {liquid is adapted to'be drawn'by a pum'p o forced by hydraulic orpneumatic press re,-

A further important featu-re of the inve'ntion consists in: means formingfpartfofithe system.- for showing the temperature of; the liquid drawn fromthetank. I 'I In one of its preferredpraotical for ms, the invention embodies two'yesse'l's which are relatively movable and are preferably connected at' their bases by, a fiexible'tubewliich together with the vessels constitutes allez rfible U tube. The U tube-contains mercury or any other suitable heavy liquid which in the operation of the apparatus"functionsfasia mobile piston. One arm 'ofthe U 'tub'ejis connected to a bell o'r air pressure cylinder positioned within .a tank and at leastj partially submerged inithe liquid'to be'measured. The'other arm of the Utub'e is vented and is also connected to the first arm of the U tube by a tube in which is interposed a trap or liquid valve embodying a reading column and functioning as a safety valve and also an indicating element. I

The vessel associated with the said first arm of the U tube is provided interiorly 1926. Serial No. 119,307.

is 0 eratively connected with the second vessel or synchronized movement therewith.

Through movement of the second vessel variations inpressure may be obtained in the arm .Qf the U 1 tube above the first vessel by the flo'w'of'the piston during movement .df thefsecond vesseland through this man'- u'al movement, the vessels maybe relatively adjusted to balance the pressure due to'the liquid head in the tank against the weight of the'piston andfwhe'n the piston has been brought into a posit-ion 'to complete the electric circuit, thepointer'will show on the dial'the level or amount ofliquid in the tank, it being understood thatthe dial is gradu;

atedtopermit.ofisuch reading. During these operations, the safety valvewi ll function to relieve'excess'pressuresl' I f It will thus be noted that the present invention'embodies, among other features, a flexible U tube adaptedfor manual'mani'pulati'onto cause thejflow of a mobile piston 'cohtained therein and during which m an pu lation'a pointer is automatically moved over a. dial'to permit readings to be made'when the pressures are properly balanced,

Features of the invention, other than those adverted to, will be apparent from the'hereinafter detailed description and claims, when read inconju'nction with the accompanylng drawings.

The accompanying drawings illustrate different practical embodiments of the invention, but the constructions, therein shown are to be understood as illustrative, only, and not as defining the limits of the invention.

Figure lis a diagrammatic showing of an indicating system embodying the present invention. In this view, the tank with WhlCh the system is to be associated is not shown.

Figure 2 is a diagrammatic view showing the system illustrated in Figure 1, as applied to a tank of large capacity.

Figure 3 illustrates certain temperature operated means shown diagrammatically in Figure 2.

Figure I shows the adaptation of the form of the invention shown in Figure 1 to a hydraulic or pressure liquid feed system.

Referring to the drawings, 1 designates a suitable casing or housing in which the operating parts of the apparatus are contained. Mounted within the casing are two vessels 2 and 3. The vessel 2 is supported on a plate 4 mounted for vertical sliding adjustment adapted to be imparted thereto by an adj ust ing screw 5. Normally, however, the vessel 2 is stationary and may be referred to as the fixed vessel. I

The vessel 3 is mounted upon a carrier 6 supported for vertical sliding movement and provided at one edge with airack 7, whereby the carrier may be reciprocated vertically to correspondingly move the vessel This vessel because of themovenient to which it is adapted may be termed the niovable vessel.

Meshing with the rack 7 is a pinion 8 fixed on a spindle 9 to which is also secured bevel gear 10. v Meshing with this bevel,' 'geai"fis a. bevel pinionll fixed on-a sliaft l'2 wh ich pro.- ject-s through the side of the casingandhas aflixd thereto a hand wheeler finger piece 13 bymeans of which the'shaft 12 maybe rotated to impart vertical movement to-the carrier 6. Also fixed on the shaft 9 isa-hand or, pointer 14 which works over a dial 15 me manner hereinafter more fully explained.

The vessels- 2 and 3 are provided with depending nipples. which are connected by a flexible tube-16 and the vessel 2 is formed with an upwardly extending neck 17, downwardly through which extendsa rodl8 which tel.- minates at about the base of the-neck. The vemcls 2 and 3 and their connecting tube. 16 collectively form a U tube substantially the opposite ends of which are enlarged to form the vessels 2 and 3. This U tube contains mercury or some other suitable heavy liquid 19 which constitutes part. of an electric circuit. lhe mercury body is connected by means of a wire 20 to one pole of a battery 21 and a wire 22 leads from the other pole of the battery to the switch 23. From the switch 23, a wire 24 leads to a bell, buzzer, or other audible or visual signal 25 and from the bell 25 a wire 26 leads to electrical connection with the rod 18. It will thus be apparentthat it the body of mercury rises in the vessel 2 sufficiently to engage .the lower end of the rod 18, an electrical circuit will be completed and the bell will be sounded. The circuit will be again broken when the mercury level falls in the vessel 2 below the. end of the rod.

In associating the present invention with a tank, I provide a bell or pressure cylinder 27, which is adapted to be positioned in the tank,

the contents of which is to be measured This pressure cylinder is open at its bottom and closed at its top except -for a tube 28 which leads from the top of said chamber to and is connected with the upper end of the neck 17 of the vessel 2. This tube mayextcnd in a'substantially uninterrupted manner from the pressure cylinder 27 to the neck 17, but in Figure 1, it is shown as extending to a header 29 to which are connected numerous other pipes 28 28", etc., corresponding to other pressure cylinders or pressure bells associated either with the same tank or with different tanks. All of the pipes 28, 28, are valved so that they may be selectively placed in communication with the header 29. The header 29 is connected by a pipe 30 to the upper end of the neck 17, but in thispipe is included a. vent valve 30 whereby the interior of the pipe may beQvented 'to the outer atmosphere.

Iinay also include in thispipe a protecting element 32'consisting of a casing havmga wire gauze partition therein to preclude'a flash back in case gases in the pipe 30 catch fire abovethe protector 32. In practice this protector 32 functions similarly to the Davy lamp principle. I 1'.

will benoted that thepipe30'is also coni ected by'a tube 31-toa glass vessel 32 into the lower portion ofwhich extends the dependneck 33 ofa secondglass vessel 34'. Mercnryor anyjot-her suitablejindicating liquid is contained within the' vessel 32 and under varying degrees of pressure, as hereinafter explained, will rise in the neck 33. The glass vessel'34 has av'ent pipe35l vhich leads to the atmosphere and'to this vent pipe is also connetted a flexible t-ube3 6 leading to the upper end of the movablevessel 3,. I It will be nmed that a graduated 37 is associated with the neck 33 of the glass tube 34-..

Wheninst'alling the'present invention in a tank, the particular method of installation will vary with the sizeof the tank. For relatively small sup'ply' tanks, such, for example, as are ordinaril used at filling stations. a single pressure cy inder 27 of a length substantially equal to the interior height of the tank is positioned within the tank. In the larger tanks, however, an arrangement, such as is shown in Figure; 2 is generally employed.

Here a plurality .of pressure cylinders 27, I

27, 27 27 and 27 are positioned at difi'erent elevations in the tank with the bottom of the successive cylinders juxtaposed with the top of the next preceding cylinder, so that, collectively, the several cylinders will cover the entire range of liquid levels in the tank. Pipes 28 lead from the several pressure cylinders to the header 29 and by opening the valves of the respective pipes in succession. an accurate reading of the liquid level can be obtained as will be hereinafter more fully explained. Suffice it here to say that the purpose of the header 29 is to allow unitary indieating means to serve a plurality of pressure cylinders either in the same or in different tanks.

After initial installation of the parts as thus far described, the apparatus operates as follows. When it is desired to take a reading, the knob or hand wheel 13 is turned in a counterclockwise direction to turn the dial pointer 14 counterclockwise and at the same time move the vessel 3 downward with its carrier 6, until it takes substantially the dotted line position of Figure 1. Mercury 19, which ordinarily substantially half fills both the vessels 2 and 3, is thereby caused to gravitate from the vessel 2 in the direction of the vessel 3. This recession of the mercury level in the vessel 2 creates a partial vacuum in the neck 17. This partial vacuum causes air to be sucked in through the pipe 30 and through the tube 31 from the small vessel 32 and such air enters the vessel 32 through the pipe 35 and neck 33 and bubbles up through the liquid in the vessel 32 to pass throughthe tube 31 and pipe 30 into the neck 17. a

This operation can be seen by watching the glass vessel 32 and the neck 33, since it is accompanied by a pronounced agitation of the liquid therein due to the bubbling of the air through the liquid. After the bubbling has ceased, and, in practice, it ceases in a fraction of a minute, the knob'13 is turned clockwise. This elevates the vessel 3 and causes the mercury to run from such vessel toward the vessel 2'with the result that thelair in the neck 17 and in the pipes 30 and 28 will be placed under pressure. This pressure will also be communicated to the glass vessel'32 and will cause the mercury to rise in the neck 33, but such pressure is not suflicient to cause air bubbles to pass from the vessel 32 through the column of mercury in the neck 33. Q

Corresponding pressure,-however, is built up in the pressure cylinder 27 and forces the liquid in such pressure cylinder out of-the bottom thereof, superfluous pressure being forced out through the liquid in the tank in the form of bubbles. This continues until an equilibrium is established between the pressure in the pressure cylinder 27 and the hydrostatic pressure of the liquid in thetank.

' The pressure to which I have referred is built up by the turning of the'knob 13 and consequent elevation of the vessel 3. By the time the condition of equilibrium, to which I have referred, has been established the vessel 3 will have been elevated to such extent as to raise the level in the vessel 2, against the pressure in the neck 17, sufficiently to complete a circuit with the rod or electrode 18 and the bell 25 Will ring. If the operator thereupon looks at the pointer 14, a reading may be had with reference to the dial 15, and this reading will show the quantity of liquid in the tank.

Moreover, the mercury column in the neck 33 is susceptible of a reading in conjunction with the graduated scale 37 and indicates ap; proximately the level of the liquid in the tank. Any time that an accurate reading is desired, it is only necessary to turn the knob 13 counterclockwise as hereinbefore described and then slowly reverse such rotation until the bell rings whereupon the pointer 14 will indicate the contents of the tank.

It will thus appear that the construction is not only simple and not apt to get out of order, but is extremely accurate. If the connections in the tank are not carefully made and slight leakage is present, this makes very little if any difference, since the invention creates pressure in the neck 17 by means of the difference in the mercury level in the adjustable U tube and if the pressure is leaking slightly, it simply means that it will take a little longer for the mercury to rise sufliciently to close the circuit to the bell. Changes of temperature occurring between the tank and the indicator casing, as well as leaks, in order to effect the reading would have to occur between the time that the bell sounded and the time that'the operator could look at the indicating pointer 14, and as these two events are practically simultaneous, the pronounced accuracy of the indication will be apparent.- 7

Since this apparatus in effect, measures distance from the lower end of the rod or electrode 18 to the level of the mercury in the vessel 3 by means of a pointer 14 operating over the scale 15, it necessarily follows that in order to be absolutely accurate, the pointer 14 should be at zero on the scale 15, when the mercury inthe vessel 3 is exactly level with the' lower end of the electrode 18. This occurswhen there is atmospheric pressure in the neck 17 off the vessel 2.. In order to check theapparatus at any time to determine its accuracy the valve 30 should be opened to vent=the system and permit atmospheric pressure-to be established therein. 1 7

After this has been done and while the valve 30 is open, the knob 13 should be turned clockwise until the buzzer operates and this should occur exactly as the pointer reaches zero on the scale 15. .Ifthere is the slightest discrepancy, corrective adjustment may be made by manipulating the thumb screw 5. Thereafter the valve 30 should be closed and the apparatus is susceptible to correct readings by manipulating the thumb screw in the manner which I have hereinbefore described.

I wish to point out that the parts 32, 33 and 34, the last mentioned of which'is vented to the atmosphere, function in practice as a safety valve. For example, if at any time and for any one of many reasons, an undesirable and abnormal pressure may be built up within the pipe 30, this pressure may escape by forcing all of the liquid from the vessel 32 up into the vessel 34, whereupon excess pressure may bubble through this liquid and exit by the pipe 35 without occasioning any damage to the apparatus.

Reference has been made to the construclion of Figure 2 and from what has been described with reference to -Figure 1, the manner of operating the arrangement of Figure 2 will be clear from this drawing, if-it be borne in mind that when operating any particular pressure cylinder, there be added to the resulting dial reading the distance at which the lower edge of such pressure cylinder is from the bottom of the tank. For example, if the reading is being taken by using the presure cylinder 27* and the dial reading is, for example, 500 gallons, this simply means that there is 500 gallons above the lower edge of the cylinder 27 and in order to ascertain the entire contents of the tank, itis only necessa to add that quantity belowrthe lower edge of-the cylinder to the dialreading in order to give the/complete contents; It can be readily ascertained and-infact marked upon the header or a suitable chart the quantity-ot liquid below'the lower edge'of: each pressure cylinders-so that inthe manner -describe-(1',- accurate n'zeasurement maybe had of the contents of tanks 'o fcalmost unlimited size by the use of small, compact. indicating means. This is a highly novel feature of the invention: v 1 E For-the reasons well known toathe art, it is desirable'when dispensing liquids, e. g., gasoline to'kuow the temperature of the liquid being drawn from the tank. .The resent invention provides means whereby t is can be readilyascertained.

In Figure 2, means is shown for accomplishing this result and this means is detailed in Figure 3. -In theseviews,- 38 is areceptacle having a neck 39 and. partly filled with mercury or any other suitable liquid-40. This receptacle is positioned within a tank, as shown at Figure 2, with-1a vent pipe 41 leading to the atmosphere and-a pipe 42 leading to the header 29. The pipe-42 extends down into the neck 39, so that asthelevel of the liquid rises and falls under changes of temperature, similarly to the operation'of the thermometer .-this rise and tallin liquid level within-the lower end of the pipe 42will pro duce variations inair pressure-within said pipe and when the corresponding valve is open ed to permit communication of such pres sure to the pipe 30 bf Figure 1. A reading may be taken by manipulation of the .knob as hereinbefore described, the dial 15 haviug a series of graduations to show temperatures as well as volumes.

This will be clearly apparent when it is noted that in the drawing the tube 39 is shown to he of smaller diameter than the tube 1-38 (see Figure For this reason, level 40 rises and falls with the temperature very rapidly as in a thermometer, the rising being effected by the change of volume of the whole liquid volume not only in-39, but also in 38. It is this change of liquid 40 that is measured by the pressure at the bottom of 42. Ohviously, it is not quite proportional to temperature as the specific gravity of the liquid changes somewhat. It is not necessary. however, that strict proportionality be maintained. All that is necessary in practice is to measure the actual pressure at two given extreme temperatures just is done when calibrating a thermometer: The proper thermometer scale is then found by dividing the difference of readings by the difference of temperatures .used for calibration.

It will further be apparent that I am able with one indicating apparatus to measure tanks of any depth or capacitygto also show the temperature of the liquid. 7 'l he construction, as thus far described, is particularly adapted for employment for installatioirwith tanks having atmospheric pressure within the tank. :In force. feetlqsystems, fsuchaas pneumatic or hydraulic: pressure tan ks, -a slight modification over :the construction shown inFigure 1 should be used as shownin Figure 4. Thetank will of coursebesealed if it'is a pressure feed system and the'pipez35 of Figure lshonld be continued-through.a suitable shut off -;valve I tof a iheader-A4 from whichf pipes v45 lead- .to the interior of the tank, so that-the pressure within the tank will be communicated to the vessels 3 and 3'4. The vent valve 30ishould-be omittedraud in lieu thereof, the-pipe BO-sh'ould-beled through a suitable shut off valve .46 to the header 29, which is connected with pressure cylinders after the mannerihegeinbefore described.

By=thus communicating pressure in the tank to oppose the hydrostatic-pressure.-in the tank andbuildingup-operating pressures for the indicating apparatus,.accurate rea'dings may be had without the use ofsprings or other extraneous cushioning means; :If the pipe 35 is not connected with the tank, the pressure in the tank wouldv probably force the mercury out of the system or would at. any rate so disorganize' the apparatus thatiaccurate readings could not be obtained;

I wish to callatten tion to the practical advantage of the liquid valve embodying'the vcssels32 and34= with the interconnect-ingncck 33. This constitutes a' feature of considerable practical importance' For example, if the valve'30' were left closed ,while the measuringoperation' was proceeded with, the lowering of the mercury column in the-chamber 2 would produce sufiicient suction int-he; pressure cylinder 27 to, in many instanccs,'draw gasoline into the neck 17. 'lhiswould particularly occur if the tubes or conduits connecting the pressure chamber were small, as they generally are in practice. Hm-rever, with a liquid trap'in the systeui, the building of excess minus pre sures (pressures less than atmospheric pressure) will cause the liquid in the neck33 to flow into the vessel 32 and the system will be vented by air which bubbles up preferred, practical forms, but because of the wide adaptability of the invention, it is not limited to this illustrative showing, but is to be considered as fully commensurate with the appended claims. 1

Having thus fully described-theinvention, what I claim as new and-desire to-secure by LettersPatentisi v 1. In a liquid-level-indicating system, a pressure cylinder-adapted to beat least partially submerged inthe liquid to be measured and provided at'its bottom' with an opening through which the liquid is free to flow into and out'of the cylinder,- a-flexible U tube containing=a liqu id piston and one arm of which U tube'isconnected by a passage to the pressure 'cylinder,-a dial, a-poin'ter movable over the dial, means-for moving the pointer over the dial and for simultaneously elevating one arm-ofthe'Wtubeto cause the liquid plston to 'ri'se in-theother arm ofth'e' U tube and place theair in the pressure cylinder, under pressure,means forixidicatingwhen the pressure in the pressure cylinder is substantially balanced with the hydrostatic pressure of the liquid to be measured, and a liquid valve communicating with the pressure cylinder and with the normally stationary arm of the U tube to relieve excess plus or minus pressures by the expulsion of air from or the admission of air into the system.

2. In a liquid level indicating system, a pressure cylinder adapted to be at least partially submerged in the liquid to be measured and provided at its bottom with an opening through which the liquid is free to flow into and out of the cylinder, a flexible U tube containing a liquid piston and one arm of which U tube is connected by a passage to the pressure cylinder, a dial, a pointer movable over the dial, means for moving the pointer over the dial and for simultaneously elevating one arm of the U tube to cause the liquid piston to rise in the other arm of the U tube and place the air in the pressure cylinder under pressure, means for indicating when the pressure in the pressure cylinder is substantially balanced with the hydrostatic pressure of the liquid to be measured, and a liquid valve communicating with the pressure cylinder and with the normally stationar arm of the U tube to relieve excess plus or minus pressures by the expulsion of air from or the admission of air into the system, said liquid valve embodying a reading column adapted to show approximately the quantity of liquid being measured. I

3. In a system of the character described, a vessel containing a liquid, the level of which changes under variations in temperature due to the expansion or contraction of the liquid, a pressure cylinder partially submerged in said liquid, a flexible U tube, one end of which is normally fixed and the other end of which is mounted for up and down movement, said fixed end being connected by a closed conduit to the pressure cylinder and the U tube containing a liquid piston, means for elevating the movable end of the U tube tocause the liquid piston to flow toward the fixed end of the U tube for the purpose of placing the air in the conduit and pressure cylinder'under pressure sufiicient to balance the hydrostatic pressure of the liquid in the-vessel, and: indieating -means for indicating s'uch balancedcondition, in terms of temperature.

4. In a system of the characterdescribed, a vessel containinga liquid; the level of which changes under variations in tem erature due to the expansion or contraction of liquid, a flexible U tuhe,one end of which is normally fixed and the other endof which is mounted for up and down-movement, saidthe movable end: of the U tube to cause the= liquid piston to flow toward the fixed end of the U tube for the purpose of placing the air in the conduit and pressure cylinder under pressure sufiicient to balance the hydrostatic pressure of the liquid in the vessel, and indicating means for indicating such balanced condition, said indicating means embodying a signal showing when the balanced condition prevails and also comprising a scale graduated for temperatures.

5. An assembly of the character described embodying a tank adapted to contain liquid to be measured, a plurality of upright pressure cylinders arranged at diflerent levels in the tank, the lower end of each cylinder being transversely juxtaposed with the upper end of the next lower cylinder, unitary indicating means, and means for placing the pressure cylinders selectively in communication with the indicating means.

6. An assembly of the character described embodying a tank adapted to contain liquid to be measured, a plurality of upright pressure cylinders arranged at different levels in the tank, the lower end of each cylinder being approximately juxtaposed with the upper end of the next lower cylinder, unitary indicating means, a conduit leading from each I the-liquid, a 1 pressure cylinder partiallysubmerged in said pressure cylinder to the unitary indicating means, and valvular means for placing the indicating means in communication with said pressure cylinders selectively.

7. In a liquid level indicating system, a

pressure cylinder adapted to be at least partially submerged in the liquid to be measured andprovided at its bottom with an opening through which the liquid is free to enter and 10 leave the cylinder, a flexible U-tube containin a liquid piston and one arm of which U- tufie is connected by a passage to the pressure cylinder, said passage having a valved vent to the atmosphere, means for lowering the arm of the U-tube which is not connected with -the pressure cylinder to cause the liquid piston to descend in the other arm of the U-tube to suck in air through the valved vent to fill said passage with air, and for thereafter elevating said arm to place the air in the pres sure cylinder under pressure equal to the hydrostatic pressure of the liquid to be measured, and indicating means operable by movement of the movable arm of the U-tube.

8. In a liquid level indicating system, a pressure cylinder adapted to be at least partially submerged in the liquid to be measured and provided at its bottom with an opening through whichthe liquid is free to enter and leave the cylinder, a flexible U tube containing a liquid piston and one arm'of which U tube. is connected by a passage to the pressure cylinder, said passage having a valved vent to' the atmosphere, means for lowering the F other arm of the U tube while the first mentioned arm remains stationary to suck in air through the valved vent to fill said passage with air, and for thereafter elevating said. arm to cause the liquid to flow in a direction to place air in the pressure cylinder under 40 pressure, a dial, a pointer mechanically connected to said means and movable over the dial as said arm of the U tube is elevated, whereby, when the ressure in the pressure cylinder and the hy rostatic pressure of the liquid to be measured are substantially balanced, a reading may be obtained by observing the dial and pointer.

9. In a'liquid level indicating system, 'a

pressure cylinder adapted to beat leastpartially submerged in the liquid to be measured, and provided at its bottom with an opening through which the liquid is free to flow into and out of the cylinder, a flexible U. tube containing a liquid piston, and one arm of which U tube is connected by a passage to the pressure cylinder, a dial, a pointer movable over the dial, means mechanically connected to the. pointer for lowering the other arm of the U tube to suck air through the valved vent to fill said passage with air, and for thereafter simultaneously moving the pointer over the 5 dial and elevating the latter arm of the U tube to cause the liquid piston to rise in the-first mentioned arm of said U tube and place the. air in the pressure cylinder under pressure,:' and means. for indicating when the pressure ,1 in the pressure cylinder. is substantially-bahanced with the hydrostatic pressure oithe, liquid to be measured.

. i In testimony whereof, JACK D. SAMA OBB. has signed his name to this specification-this 24th day of June, 1926. 4 a

JACK D SARTAKOFF, 

